<?php
    use yii\helpers\Url;
?>
<html>
    <head>
        <title>title</title>
    </head>
    <body>
        <form enctype="multipart/form-data" method="post" action="<?php echo "?r=".url::to('file/upload') ?>">

            <input type="file" name="file"/>
            
            <input type="text" name="aa"/>
            
            <input type="submit" value="submit" />
        </form>
    </body>
</html>
